1. Field of the Invention
The present invention relates to an erasable recording material having a marker, in which image information can be reversibly recorded and erased and to which additional information written on the recording material can be added to the image information using the marker, and to an information recording system and an information recording method using the recording material.
2. Discussion of the Related Art
Recently, a huge amount of paper is used and disposed of, and there are serious social problems as to how to treat the paper dust and how to protect forests in the earth. There is a trend in the world to protect the environment of the earth, and various measures such as recycles of copied paper, are popularly performed in the world to reduce paper dust. One of the measures, erasable recording materials, in which images can be reversibly recorded and erased, have been increasingly developed.
In addition, recently information processing methods have been researched and developed in which microcomputers having a data memory and a display and paper are used as devices which can store and display a variety of information such as characters and images while taking full advantages of the microcomputers and paper.
Japanese Laid-Open Patent Publication No. 9-101864 discloses an information processing apparatus which is constituted of an information displaying medium which is shaped like paper and which can erasably display a variety of information, an information storage medium and an information recording apparatus. A variety of information, e.g., information prepared in a computer and information input by hand, can be erasably displayed in the information displaying medium. Since the information can be handled as digital information which can be processed by a computer, the information can be stored in the storage medium or can be output. However, this apparatus has a drawback in that the information displaying medium must be set to a predetermined position, for example, by clipping, in order to make the memory or the computer output information as to which part in the information displaying medium input information is input. In other words, the precise position of the input information in the information displaying medium cannot be identified in such an information processing apparatus.
Japanese Laid-Open Patent Publication No. 6-222877 discloses a method in which at first a standard point is established by pressing a pen serving as an input device, and then the position of information is determined as a relative position to the standard point. This proposal has an advantage in that the apparatus has good portability because a tablet or the like, which provides position information, is not used. However, this proposal has a drawback in that the same standard point cannot be selected in every time when the operations are repeated because any point in the paper can be selected as the standard point. Therefore, the method cannot provide precise position information.
In addition, Japanese Laid-Open Patent Publication No. 8-36452 discloses a writing pen device in which information of recorded images is determined using the difference in light reflection characteristics between red patters and green patterns formed on the information displaying paper medium. This device can provide precise position information even when a user freely input information in the information displaying paper medium. However, the red and green patters are not needed for users, and in addition the patterns make information displayed on the paper medium difficult to see. Further, the aesthetic value of the information is deteriorated by the red and green patterns. Furthermore, the information displaying medium is a paper medium and therefore cannot be reused. Therefore, the running cost is increased in the writing pen device.
In addition, in the information processing apparatus disclosed in Japanese Laid-open Patent Publication No.9-101864 mentioned above, when new information is desired to be added in plural information displaying media having information to prepare new documents (information including characters, images and the like), the new information is added therein while each of the plural information displaying media is set on the information recording apparatus one by one, and therefore it is a troublesome operation. A method is disclosed in the publication that the old and new information in each information displaying media are stored in the information storing medium. In this method the information as to in which pages the new information has been added cannot be known because each of the plural information displaying media is not identified.
Japanese Laid-Open Patent Publication No. 7-200134 discloses a method for identifying an information displaying medium set on a recording apparatus. The method is that identification information such as a barcode is printed on an upper part of each recording medium and in addition an identification information detecting device is set to an upper part (e.g., a clipping device) of the board, on which the recording medium is to be set. However, in the method the medium is made of paper, and therefore information cannot be reversibly recorded and erased. In addition, since the identification mark such as a barcode is printed on the medium, the space of the medium in which information should be recorded is decreased. Further, the identification mark is an eyesore for persons reading the recorded information.
Japanese Laid-Open Patent Publication No. 5-124360 discloses a magnetic recording layer is additionally formed on an information displaying medium. The information stored in the magnetic recording layer is invisible and the space of the recording medium in which information is to be recorded is not decreased if the magnetic recording layer is formed on the back side of the displaying medium. However, if the information displaying medium is used in the information processing apparatus disclosed in Japanese Laid-Open Patent Publication No. 9-101864, the recording apparatus becomes complex. In addition, the magnetic recording layer is troublesome to handle because the magnetic recording layer is easily affected by magnetism and therefore has to be handled carefully.
Because of these reasons, a need exists for an erasable recording system in which information can be freely rewritten in an erasable recording material and in which additional information written on the recording material can be added in the recording material to prepare a new document.
Accordingly, an object of the present invention is to provide an erasable recording material in which image information is reversibly recorded and erased and in which additional information written on the recording material can be input to a memory storing the image information previously recorded in the recording material.
Another object of the present invention is to provide an information recording system using the recording material, in which additional information written by an inputting device on the recording material can be incorporated in the previously recorded image information and then the previous image information and the additional information are output in the recording material.
Yet another object of the present invention is to provide an information recording method, in which additional information written by an inputting device on the recording material can be incorporated in the previously recorded image information and then the previous image information and the additional information are output in the recording material.
To achieve such objects, the present invention contemplates the provision of an erasable recording material which includes a substrate, an erasable recording layer formed on the substrate and a marker (i.e., information carrier) which is used for adding additional information written on the recording layer to previously recorded information in the recording layer and a memory.
The marker is preferably invisible, or the optical density of the recording material in which the marker is present is not greater than twice or less the optical density of the recording material in which the marker is not present. In addition, the marker is preferably detected by an optical detecting method.
The marker preferably includes an infrared absorbent selected from the group consisting of oxides, sulfides and halogenides and their complexes, which include an element selected from the group consisting of Nd, Yb, In, Sn or Zn. Alternatively the information carrier may include a material which emits a fluorescent light.
The erasable recording material preferably includes an erasable thermosensitive recording layer in which visible information can be reversibly recorded and erased by changing its optical properties upon application of heat. The erasable thermosensitive recording layer is preferably a layer including a leuco dye and a color developer, or a layer including a resin and a particulate organic compound having a low molecular weight.
The erasable recording material optionally includes an undercoat layer, an intermediate layer, and/or a protective layer. The marker may be included in the recording layer, undercoat layer, intermediate layer and/or protective layer, or maybe formed therebetween or on the substrate. The erasable recording material may include a marker layer which includes a marker.
The marker may be a position information carrier or an identification information carrier. In addition, the recording material of the present invention may include two or more markers or two or more kinds of markers.
The present invention also embraces an information recording system, and an information recording method using the recording material mentioned above.
These and other objects, features and advantages of the present invention will become apparent upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.